Add gn_isolate_map.pyl file for WebRTC stand-alone tests

With this, MB can be invoked with the new --isolate-map-file flag
that was added in https://codereview.chromium.org/2443643002.

BUG=chromium:497757
NOTRY=True
TESTED=Created /tmp/foo and filled it with targets from https://build.chromium.org/p/client.webrtc/builders/Linux32%20Debug/builds/9305/steps/generate_build_files/logs/swarming-targets-file.txt
Then I sucessfully ran:
tools/mb/mb.py gen -m client.webrtc -b 'Linux32 Debug' --config-file webrtc/build/mb_config.pyl --swarming-targets-file /tmp/foo --gyp-script=webrtc/build/gyp_webrtc.py --isolate-map-file=webrtc/build/gn_isolate_map.pyl //out/Debug

Review-Url: https://codereview.webrtc.org/2454963002
Cr-Commit-Position: refs/heads/master@{#14795}
diff --git a/webrtc/build/gn_isolate_map.pyl b/webrtc/build/gn_isolate_map.pyl
new file mode 100644
index 0000000..62d15c8
--- /dev/null
+++ b/webrtc/build/gn_isolate_map.pyl
@@ -0,0 +1,102 @@
+# Copyright (c) 2016 The WebRTC project authors. All Rights Reserved.
+#
+# Use of this source code is governed by a BSD-style license
+# that can be found in the LICENSE file in the root of the source
+# tree. An additional intellectual property rights grant can be found
+# in the file PATENTS.  All contributing project authors may
+# be found in the AUTHORS file in the root of the source tree.
+
+# gn_isolate_map.pyl - A mapping of Ninja build target names to GN labels and
+# test type classifications for the tests that are run on the bots.
+#
+# This file is based on testing/buildbot/gn_isolate_map.pyl for Chromium, but
+# is covering WebRTC stand-alone tests instead.
+# See https://cs.chromium.org/chromium/src/testing/buildbot/gn_isolate_map.pyl
+# for more detailed documentation.
+
+{
+  "All": {
+    "label": "//:All",
+    "type": "additional_compile_target",
+  },
+  "AppRTCMobileTest": {
+    "label": "//webrtc/examples:AppRTCMobileTest",
+    "type": "additional_compile_target",
+  },
+  "android_junit_tests": {
+    "label": "//webrtc:android_junit_tests",
+    "type": "junit_test",
+  },
+  "audio_decoder_unittests": {
+    "label": "//webrtc/modules/audio_coding:audio_decoder_unittests",
+    "type": "console_test_launcher",
+  },
+  "common_audio_unittests": {
+    "label": "//webrtc/common_audio:common_audio_unittests",
+    "type": "console_test_launcher",
+  },
+  "common_video_unittests": {
+    "label": "//webrtc/common_video:common_video_unittests",
+    "type": "console_test_launcher",
+  },
+  "libjingle_peerconnection_android_unittest": {
+    "label": "//webrtc/api:libjingle_peerconnection_android_unittest",
+    "type": "additional_compile_target",
+  },
+  "modules_tests": {
+    "label": "//webrtc/modules:modules_tests",
+    "type": "console_test_launcher",
+  },
+  "modules_unittests": {
+    "label": "//webrtc/modules:modules_unittests",
+    "type": "windowed_test_launcher",
+  },
+  "peerconnection_unittests": {
+    "label": "//webrtc/api:peerconnection_unittests",
+    "type": "console_test_launcher",
+  },
+  "rtc_media_unittests": {
+    "label": "//webrtc/media:rtc_media_unittests",
+    "type": "console_test_launcher",
+  },
+  "rtc_pc_unittests": {
+    "label": "//webrtc/pc:rtc_pc_unittests",
+    "type": "console_test_launcher",
+  },
+  "rtc_stats_unittests": {
+    "label": "//webrtc/stats:rtc_stats_unittests",
+    "type": "console_test_launcher",
+  },
+  "rtc_unittests": {
+    "label": "//webrtc:rtc_unittests",
+    "type": "console_test_launcher",
+  },
+  "system_wrappers_unittests": {
+    "label": "//webrtc/system_wrappers:system_wrappers_unittests",
+    "type": "console_test_launcher",
+  },
+  "test_support_unittests": {
+    "label": "//webrtc/test:test_support_unittests",
+    "type": "console_test_launcher",
+  },
+  "tools_unittests": {
+    "label": "//webrtc/tools:tools_unittests",
+    "type": "console_test_launcher",
+  },
+  "video_engine_tests": {
+    "label": "//webrtc:video_engine_tests",
+    "type": "console_test_launcher",
+  },
+  "voice_engine_unittests": {
+    "label": "//webrtc/voice_engine:voice_engine_unittests",
+    "type": "console_test_launcher",
+  },
+  "webrtc_nonparallel_tests": {
+    "label": "//webrtc:webrtc_nonparallel_tests",
+    "type": "console_test_launcher",
+  },
+  "xmllite_xmpp_unittests": {
+    "label": "//webrtc:xmllite_xmpp_unittests",
+    "type": "console_test_launcher",
+  }
+}